Donatello: Genius
by Therandomer5000
Summary: Part 3 in the Family Roles series. Donnie is working hard on a retromutagen but he's getting nowhere fast, and now he's run out of ingredients. What will he do? How far will he go to save the humans from their fate? Can he prove himself as the Hamato clan's genius? R&R x


**Part 3! Donnie's turn! Only one more one shot left in the series! Enjoy x**

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**Family Roles**

**Part 3**

**Donatello: Genius**

It had been two weeks since Raphael had saved them from a hoard of mutated humans. The first week was spent together healing and resting. The second Donnie spent every minute in his lab trying his hardest to create a retromutagen. He knew this was the next step, the thing keeping him and his brothers from going topside and saving those poor people. He had worked tirelessly for months before hand but never had anything close to what he was looking for.

Now he felt himself inches away from a solution but due to being unable to travel topside he could no longer gather the supplies he needed; he was now on his last batch.

His last hope.

His brothers and father continuously supported him, assuring him that he'd get there soon.

They didn't realise their support was causing more harm than good.

Donnie hated himself for letting them down over and over, he hated his family for the pressure they were putting on his shoulders. He felt as if he was a failure and that his family would realise it too soon enough.

He shook his head, he needed to concentrate as he poured the pink solution onto the last drops of mutagen. If it stayed stable, then he'd done it.

But of course, the universe is not that kind.

The minute his newest solution hit the mutagen it fizzled and popped, he yelped as it rose to the top of the container and spilled out onto the desk. He rushed to grab a towel and clean up the mess, he deflated at the large stain that remained.

He flopped back into his seat and continued to stare at the offending stain dully.

"This is hopeless" He sighed quietly to himself, "I'm never gonna make a solution… All I make is a mess and now I have no ingredients"

He raised a hand and pounded his forehead with it angrily.

"Think dumbass! Think! Think! You're supposed to be the smart one! The Brainiac!" He snarled before letting his hand drop down at his side, he knew his forehead had a red mark now but found he didn't care.

He was a sham. A fake. He was no smarter than the rest of them.

He was no Brainiac. No genius. Just a hopeless idiot.

These thoughts weighed heavily on his mind as he shut his eyes, he felt so lost. What was he going to do now?

Go topside. Find the ingredients he needed and get straight back to work.

Then maybe he could prove himself as the genius of the family.

But he wasn't allowed topside. Their father had made that very clear after the last incident, it was dangerous up there for them now. More so than usual.

He sighed again as he thought about the risks.

He needed to do it, or they'd never be able to go topside again. The risk was worth the reward.

He just needed to wait until night-time.

He needed to have a think about where would have all the ingredients he needed.

His immediate first thought was Shredder's lab but that would be suicide.

Convenient due to the mutants living there but suicide.

He figured though that if he couldn't find what he needed anywhere else then Shredder's lab would be a fantastic last resort. He briefly wondered what his brothers would think of his plan.

He jumped when he heard the knock at the door.

"Donnie? C'mon bro! You gotta need some brain food by now!" Mikey childishly whined through the metal, "We've not seen you all day! You missed breakfast and lunch!"

"He's missed two meals!? You said you saw him at breakfast!" Leo gapes as he too begins knocking at the door. "Donnie! Get your shell to the table!"

"See D! I covered for you! You owe me!" Mikey calls, "Come get food!"

"Don't make me break this door down Brainiac!" Raph snaps. Donnie flinches at the nickname.

"I'm coming!" He calls tiredly.

He pulls himself out of the chair and opens his lab door only to be greeted by three angry faces.

Mikey immediately grabs his arm and pulls him to the kitchen.

"You're never gonna make a retromutagen without food" Leo lectures. "Your brain needs fuel to work!"

"For a genius you sure are stupid!" Raph scolds, "Your health should come first"

Donnie rolled his eyes.

"Food makes no difference" He sighs as a plate is popped in front of him. "No matter what I do I can't make this stupid cure! I'm not good enough"

The brothers sit with him.

"Don't you dare think like that! You are good enough Donnie that's why we know you'll get there eventually" Leo insists using his leader voice to get his point across.

Donnie sighs he looks down into his plate. Shredded chicken, potato wedges and spinach all lovingly made by Michelangelo.

He downs the spinach first.

"I'm never going to get there" He mumbles, "I don't even know how to make a cure, it's not like I've got anyone to teach me"

"Listen to Captain Leo!" Mikey commands in his best pirate voice, "Or he'll make ya walk the plank!"

He withers at the look Raphael sent him.

"Remember our talk Mikey?" He asked through gritted teeth.

"No making jokes during serious conversations" Mikey grumbles, "But they're the best times!"

Splinter walks into the kitchen and fills a teapot up with water.

"I am glad to see you finally taking care of yourself" He says as he places it on the hob, he waits for it to boil and gets his teacup ready. "You have put far too much pressure on yourself"

Donnie quickly shoves some chicken in his mouth to prevent saying something stupid.

"He doesn't think he can make it" Mikey informs his father," He's giving up! You said we must never give up!"

"That is true my son" Splinter nods. "Tell me Donatello, how is your progress so far?"

"Nada" Donnie grumbles as he pushes the food around his plate, "There's no progress whatsoever. I'm no closer to finding anything, in fact I'm probably further away than ever!"

"And why is that?"

"Because I'm out of mutagen and all the other ingredients I need… Everything I need is topside" He explains before taking a chance, just in case he doesn't need to sneak out later. "If I could just nip up there for a second I could- "

"No way!" Raph immediately snaps. "There's no way we can go up there right now! Just use some other science-y stuff!"

"Yeah maybe you're using the wrong stuff!" Mikey nods.

"But- "

"No Donnie" Leo commands, "You are not going topside, it's too risky"

"Then what do you want me to do?" Donnie demands, "I have nothing to make retromutagen now! You wanna just stay down here forever? Let all the humans die? Let Shredder win?"

"Do not be so dramatic Donatello" Splinter soothes as he pours his tea, "We will think of something. You and I will have a chat tomorrow morning about our options, until then you will eat and rest. You have nothing to do in your lab now after all"

Donnie nods stiffly and watches his father leave the room before glaring at his brothers.

"Don't be mad at us D!" Mikey pleads, "We could barely handle those mutants when there was four of us, if you went out on your own then…"

Mikey can't seem to finish the sentence; the room goes silent.

"I wouldn't go near the mutants" Donnie insisted weakly, "I'm useless down here with no mutagen…"

"As long as you're alive you're useful" Leo says gently. "Please Donnie, it's too dangerous. Just drop it"

"But I- "

"We said drop it" Raph warns, Donnie sighs and shuts his mouth. "Finish eating then go to bed"

Both eldest brothers leave the kitchen.

Michelangelo watches Donnie as he finishes his dinner and washes his dishes.

"Please don't do this Donnie" He begs quietly, Don looks surprised at the serious tone, "I know what you're planning, I'm not stupid"

"I'm not planning anything" Donnie goes to walk out of the kitchen, but Mikey's voice stops him.

"Fine but… Please call me if you need help… If you're in trouble" Mikey gets up and walks passed Donnie, "We'll be there. Just… be careful bro"

Donnie watches his little brother go to bed; he looks around. The lair is silent, his family resting or asleep.

Now was his chance.

He went to the lab and grabbed his bo, he spun it before popping it on his belt. He walked out of the lair without a sound and headed topside.

Once out of the sewers he kept to the shadows, he wanted to check a few places before heading to Shredder's. No need to put himself in unnecessary danger.

He first ventured to a lab's garbage alley, he looked through each of the black bin bags but soon came up with nothing. Scientists aren't really testing on mutagen.

He then ventured to TCRI to have a look around the outside of the building for any dropped canisters. Nothing again.

He searched every place in the city that might have anything he needed but alas there was nothing, it made sense.

Before he knew it, he was standing on the roof to the Foot headquarters. He figured he would sneak inside, see if what he needed was there, steal it and run home.

He briefly wondered if he should call Michelangelo but figured he wasn't actually in trouble yet.

He headed in and snuck through the corridors, he found all the human mutations were in the room they had been created in. All were asleep and being injected with more mutagen. He shook his head and carried on.

He arrived at the lab and peaked in; he was surprised that no one was around. The lab looked to be shut down for the night.

He walked in and shut the door behind him, with the flick of a switch everything was ready to go, and he even saw everything he needed to make his retromutagen. There was even a huge tank of the stuff.

This was perfect.

He noticed a huge water tank in the back of the lab, he took a closer look to see it was for the sprinklers around the building and an idea came to his head. If he created the retromutagen here then he could drain the water tank, fill it with the cure and spray all the victims. Freeing them all at once!

It was stupid, dangerous. Brilliant.

He wanted to immediately set to work but knew he had made a silent promise, he picked up his T-phone and called Mikey.

"_H-Hello? Donnie?"_

"Hey Mikey, you sleeping?" he whispered

"_I was… why're you-?" _There's a gasp, _"Are you topside? Are you in trouble?"_

"No not yet… Mikey I'm about to do something really stupid" Donnie admitted, "But it could change everything"

"_If it's stupid don't do it!"_

"I have to do it… Sorry Mike"

"_Send me your location now!"_

"Wh- no! If you guys come here and it goes wrong- "

"_Location. Now!"_

"Mikey I'm serious"

"_Fine" _There's movement before Mikey starts yelling. _"DONNIE WENT TOPSIDE! HE'S DOING SOMETHING STUPID! WAKE UP!"_

Don cringes as he hears Leo and Raph practically fall out of their rooms.

"_He's where?" _Leo's voice asks angrily.

"_Topside."_ Mikey answers smugly. _"Ok D. Send us your location or we'll go topside and hunt for you"_

"Ugh. Shredder's lair" Donnie groans but hangs up, now he needs to get to work and find a way to only spray the Mutations' room just in case his bros turn up.

He takes three tiny drops of mutagen and sets to work.

The first one is heated up, the second cold and the other he tries using a different enzyme. He watches as each of the temperature ones drop and rise while he adds the enzyme.

He holds his breath and prays.

"Please just let this work. I beg of you!"

All three samples react and Donnie groans in frustration.

"I don't have time for failure" He hisses and extracts another tiny droplet of mutagen. "What haven't I tried"

He tries 5 more times, all failing until he finally decides to try something entirely new.

He takes his mutagen adds the various chemicals he used before but this time he adds water. He never once thought to dilute the mixture but maybe that's what he needed to balance the PH; the mixture had been far too acidic.

He adds a small amount of water before mixing it all together.

This time no reaction.

He grins in triumph!

He hurries to write down the process on his notes in his phone before scaling it up to work in the vat of mutagen. Soon the green/blue turns to a brownish orange, he immediately empties the water tank all over the floor. He hurries to use a pipe to drain the retromutagen from its tank and put it in the water tank.

He then hurries to the computer and sets to work hacking the fire safety program, he turns on the security camera to that room. He notes the creations are still asleep.

He activates the sprinklers.

A grin splits his face as he watches his cure rain down on the mutants, they leap up ripping the tubes out of their arms. His grin faulters as the creatures scream and fall down as their bodies morph.

He holds his breath waiting for humans to stand up.

It feels like years until finally a young woman struggles to her feet, rubbing her head. The other humans soon follow suit much to Donnie's joy.

"YES!" He cheers and jumps on the spot. "I DID IT! I DID IT!"

"You certainly did" Donnie spins around to see Shredder standing behind him. The man isn't wearing his helmet anymore, the mutagen seemed to make him grow huge, blade-like horns. Donnie grabs his Bo but before he can pull it out the gauntlet is thrust against his throat. He doesn't dare move.

He was at Shredder's mercy.

He gulped and slowly lowered his hands.

"We won" He looks Shredder in the eye proudly. "You lost. You tortured and experimented on those humans and now they're free."

"They may be free for now. Humans are very easy prey" Shredder snarls. "But you are forgetting something turtle, I now have your mutagen cure. You and your brothers are now mine to destroy"

Donnie's eyes widened.

If there was even a drop left in the tank Shredder's scientists could replicate it, he needed to do something!

"There won't be enough" He growled back, "And your scientists are too useless to replicate it"

"I don't need my scientists to do that. I have you" Shredder chuckles, Donnie pales.

"What do you mean?" Don breathes.

"You are my prisoner now Donatello" Shredder laughs as a couple of foot ninja rush into the lab. "You will create more of this cure for me then you will be the first to test it. I will even keep you alive in your pathetic turtle form to show your disgusting family"

Don curls his lip and foot ninja grab each of his arms. Shredder finally pulls the gauntlet away from his throat.

Donnie takes his chance. He spins around surprising the ninja and hurries to the control panel; he sprays out the last of the retromutagen.

He grins in sad triumph; he closes his eyes and Shredder grabs the back of his neck dragging him backwards.

A blade slices his plastron before he's kicked to the floor.

He circles an arm around the wound, it's not fatal but it would take a long time to heal. If he had time of course. He looked up into the Shredder's face, he watched as a large sword was pulled out from the Shedder's belt.

"You are a fool" Shredder growls.

"I'll never work for you!" Donnie snaps back defiantly, "And now you have no samples left! It's over Oroku Saki! Your plan has failed!"

"No matter" Shredder smirked. "I can still kill one turtle"

Donnie pulled his Bo out and just managed to block the blow, but the sword was heavy, Shredder was strong, and he was not at his peak due to a week of almost no food or rest. His arms shook as he tried desperately to keep the blade away from the sensitive skin over his throat.

"I have all night" Shredder grinds out, almost gleefully. "I have dreamed of spilling a turtle's blood for so long… I only wish your disgusting family were here to watch. How delicious it would be to watch Hamato Yoshi lose another child"

Donnie growls and finds himself gaining strength from the statement.

"DONATELLO!" He whips his head round to see his father and brothers at the door watching him in horror. He quickly turns his attention back to his would-be murderer. Distractions would cost him his life.

"Ah" Shredder smiles. "Just what I wanted"

"You leave my son alone Saki!" Splinter snarls as he runs at Shredder with his own blade.

"Your precious son trespassed on my property, he brought this upon himself!" Shredder growled but whipped away from Don to defend himself against Hamato Yoshi.

Donnie collapsed back and pants, he had held on well.

He blinks as his three brothers gather around him. Leo takes off his mask along with Raph and desperately tries to stem the blood flow.

"Donnie!" He gulps.

"I know… I'm an idiot" He groans.

"No, you're a genius!" Leo shakes his head in amazement. "You saved all the humans! Taking on Shredder by yourself wasn't the smartest but I'm just gonna blame that on lack of sleep"

"How about lack of choice?" Donnie smirks but gasped in pain at the pressure against his cut.

"Sorry" Leo winces in sympathy.

"Splinter's gonna kill him bro" Raph assures him, "Then we can all go home and get you patched up!"

Donnie smiled tiredly and nodded.

"Shouldn't you guys be helping him?"

They heard Shredder's armour smash against the floor.

"He can handle him by himself" Mikey smirks but the worry still shines through, "It's you we're worried about"

Donnie pushes Leo's hand away to get a better look at the wound, he only gets to see it briefly, but he does realise it's deeper than he thought.

"It's not fatal" He explains weakly, "The wound anyway… I'm losing too much blood; I need to get home soon"

The brothers pale and nod shakily.

"No no! I'm ok" He soothes immediately, "Not there yet… might need a transfusion if we're much longer though"

The brothers calm at that.

"My sons!" Splinter calls out. The brothers look around in shock to see sparks flying from ripped cables and the room starting to cave in. "We must go! Now!"

He rushes over to his children and scoops Donnie into his arms.

The four mutants run out of the building as the fifth fell unconscious in the safety of his father's arms.

…

"He's still not awake" Mikey's voice comes from somewhere above him. Donnie is slowly becoming aware.

He feels the bed below him and the covers over him, he feels the slight pull of his wound as he breathes.

He's alive.

"He's getting there" Leo's voice is gentle. "Be patient"

"I swear he is getting so much rest after this! No lab for a month!" Raph growls quietly.

"Aww man! D's not gonna like that!" Mike giggles.

"It's what he gets for scaring us!" Raph replies sounding miffed.

Donnie groans and slowly blinks his eyes open.

"A whole month?" he mumbles tiredly, "Shredder shoulda killed me"

"Don't even joke about that Brainiac" Raph frowns but helps Donnie to prop himself up better.

The brothers smile at him.

"Sorry" He shrugs. "Blood loss knocked me out huh?"

"Yeah but you've been given some of Mikey's so you're all good" Leo nods, "You just need to eat and rest, let that wound heal"

"Yeah! It looked nasty D!" Mikey shudders, Donnie inspects the bandage.

"I'll recover" He smirked.

Splinter enters the lab with a glass of water and a cookie.

"I am glad to see you awake my son" He greets as he hands the two things over, "Let's get your blood sugar back up, shall we?"

"Thanks Sensei" Don smiles as he sips the water before taking a bite out of the cookie.

"I am very proud of you Donatello" Splinter praises. "You have saved many lives tonight"

Donnie cringes, he can feel the 'but' coming.

"But you also ignored our rule, snuck out of the house, entered the Foot Headquarters, put yourself in danger and nearly got yourself killed by the Shredder" Splinter continued gently yet sternly. "For this you must be punished"

Donnie sighed and looked up at his father with the best puppy dog eyes he could muster.

"What's the punishment going to be?" he asked warily.

Splinter pretends to think about it.

"A month of no access to your lab" Splinter nods before smirking, "And a month of letting your brothers take care of you. I believe this wound will take time and patience to heal, you will need the help"

Donnie cringes as his three brothers cheer and smirk.

"Ok" He agrees begrudgingly, "Deal"

Splinter nods.

"Good. Rest up my son, well done" The old rat nods before leaving the room, the brothers settle down for the night.

"You guys really gonna sleep in those chairs?" Donnie asked over a yawn, "Won't you be uncomfortable?"

"Worth it bro" Mikey shrugged sleepily. "We easily could've lost you today"

"We aren't leaving your side for a while" Leo admits, "Better get used to it"

"I just mean there are other beds you could wheel over; we have four of them" Donnie smiles. The brothers hurry to bring the beds over and settle down again.

"Ya did good today Brainiac" Raph nods tiredly as he tries not to fall asleep just yet.

"Yeah, real good" Leo nods. "You're a genius Donnie"

"Our genius" Mikey mumbles as he falls asleep.

Donatello grins fondly. Yeah, he was their genius.

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